Display panel having repair lines and signal lines disposed at different substrates

ABSTRACT

A liquid crystal display panel includes a repair line for substituting open-circuited signal lines. Signal lines are disposed over a first side of a first substrate of the liquid crystal display panel for data transmission. Repair lines are disposed over a first side of a second substrate of the liquid crystal display panel for substituting open-circuited signal lines. The first side of the first substrate faces the first side of the second substrate. A liquid crystal layer is disposed between the first and second substrates of the liquid crystal panel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display panel, and more particularly,to a liquid crystal display (LCD) panel having a plurality of repairlines and signal lines disposed at different substrates.

2. Description of the Prior Art

Liquid crystal displays (LCDs) have advantages over certain otherdisplays, including advantages of portability, low power consumption,and low radiation emissions. The LCDs have been widely used in variousportable information products, such as notebooks, personal digitalassistants (PDAs), video cameras, and other similar devices.Furthermore, CRT monitors are being replaced by the LCD.

A general architecture of the LCD panel includes a thin-film transistor(TFT) substrate, a color filter (CF) substrate, and a liquid crystallayer between the two substrates. The TFT substrate includes a pixelmatrix composed by a plurality of data lines and a plurality of scanlines. The pixel matrix of the TFT substrate, formed by the plurality ofdata lines and the plurality of scan lines, includes a pixel driver ICformed by electrical components such as a TFT and a capacitor installedat each intersection of each data line and each scan line. The pixeldriver IC can receive a video data signal transmitted from the data lineand a switch/address signal transmitted from the scan line to controloperation of the corresponding pixel. In order to prevent an opencircuit in the signal transmission of the data line or the scan line, inmanufacturing the LCD panel, a plurality of repair lines is usuallydisposed in a peripheral area of the panel so that when an open circuitoccurs in the transmission of external video data signals or theswitch/address signal, the signals can still be transmitted to the LCDpanel via the repair line for controlling the pixel operation such thatpoor display quality of the LCD panel due to the open circuit of thedata line or scan line can be prevented.

FIG. 1 illustrates a top view diagram of a TFT substrate of aconventional LCD panel 10. The TFT substrate of the LCD panel 10includes a plurality of parallel data lines D1-Dm and a plurality ofparallel scan lines S1-Sn disposed in a display area 20. The data linesD1-Dm and the scan lines S1-Sn are intersecting and form a pixel matrix12. Each pixel and corresponding pixel driver IC formed by electricalcomponents such as TFTs and capacitors is represented as a dot inFIG. 1. A source driver IC and a gate driver IC are packaged in a tapecarrier package (TCP) manner and are represented as TCPs 24 and 26 ofFIG. 1. The data lines D1-Dm can be coupled to a printed wiring board(PWB) 14 through the TCP 24 and can receive signals transmitted from thesource driver IC, and the scan lines S1-Sn can be coupled to a PWB 16through the TCP 26 and can receive signals transmitted from the gatedriver IC. Repair lines T1-Ts of the LCD panel 10 can be disposed in anarea outside of the display area 20 of the TFT substrate as a backuproute for transmitting signals when an open circuit occurs in the datalines D1-Dm. Under normal circumstances, the repair lines T1-Ts and thedata lines D1-Dm are not electrically connected.

FIG. 2 illustrates a resolution for a conventional LCD panel 10 when anopen circuit occurs in a data line. If the open circuit occurs at apoint ▴ of the data line Dm (the open circuit is illustrated as “x” inFIG. 1), the conventional method utilizes a laser welding method toconnect a point B and a point C of the data line Dm to two ends of therepair line T1. The connecting point of the data line Dm and the repairline T1 after the laser welding is illustrated as ▴ in FIG. 2, and thearrows in FIG. 2 represent the signal transmission route at this moment.The normal signal transmission route starts from point B and continuesto point C of the data line Dm, however, if an open circuit occurs inthe data line Dm, the signal will be transmitted from point B to point Cof the data line through the repair line T1. In other words, the signalhas to pass through the topside, left side, and bottom side of thedisplay area 20 before transmission is completed. The resultingresistance value will be too high because the transmission route is toolong. More specifically, a resistance: RC delay effect is easilygenerated with the liquid crystal layer, hence the success rate ofrepairing the open circuited line is reduced. Furthermore, thistechnique increases the power consumption of the LCD panel 10.

In the architecture of the conventional LCD panel 10, the data linesD1-Dm, the scan lines S1-Sn, and the repair lines T1-Ts are disposed onthe TFT substrate. In order to avoid affecting the operation of thepixel, the repair lines T1-Ts must be disposed outside the display area20, such that the lengths of the repair lines T1-Ts are longer thanthose of the data lines D1-Dm, making the transmission route provided bythe repair lines T1-Ts too long, the resistance value too high, and theRC delay effect too easily generated with the liquid crystal layer,hence the success rate of repairing the open circuited line is loweredand the power consumption of the LCD panel 10 is increased. Furthermore,after the components, such as the data lines, the scan lines, and thedriver ICs, are disposed on the TFT substrate, there is limited spaceleft to dispose the repair lines. Therefore, the conventional LCD panel10 can only provide a limited amount of space for repair lines and therepair capability is insufficient.

SUMMARY OF THE INVENTION

The present invention discloses a display panel having a plurality ofrepair lines and a plurality of signal lines formed at differentsubstrates. The display panel comprises: a first substrate, a pluralityof signal lines being formed over a first side of the first substratefor data transmission; a second substrate, a plurality of repair linesbeing formed over a first side of the second substrate, and the firstside of the second substrate faces the first side of the firstsubstrate; a plurality of first connecting wires formed over the firstsubstrate, intersects with a first end of the corresponding signallines, and coupled to a first end of the corresponding repair linesthrough an electrical conductive material; and a plurality of secondconnecting wires formed over the first substrate, intersects with asecond end of the corresponding signal lines, and coupled to a secondend of the repair lines through the electrical conductive material.

These and other objectives of the present invention will become moreapparent to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view diagram of a TFT substrate according to aconventional LCD panel.

FIG. 2 illustrates a resolution for a conventional LCD panel when anopen circuit occurs in a data line.

FIG. 3 illustrates a top view diagram of a TFT substrate of an LCD panelaccording to an embodiment of the present invention.

FIG. 4 illustrates a top view diagram of a color filter substrate of anLCD panel according to an embodiment of the present invention.

FIG. 5 illustrates a cross-sectional diagram of a color filter substrateof an LCD panel along a sectional 5-5′ direction, according to thepresent invention.

FIG. 6 illustrates a cross-sectional diagram of the LCD panel alongdirection of the repair line R1, according to an embodiment of thepresent invention.

FIG. 7 illustrates a resolution for an LCD panel when an open circuitoccurs in a data line, according to an embodiment of the presentinvention.

FIG. 8 illustrates a cross-sectional diagram of the color filtersubstrate of the LCD panel along the sectional 8-8′ direction, accordingto an embodiment of the present invention.

FIG. 9 illustrates a cross-sectional diagram of the color filtersubstrate of the LCD panel along the sectional 9-9′ direction, accordingto an embodiment of the present invention.

FIG. 10 illustrates a cross-sectional diagram of the color filtersubstrate of the LCD panel along the sectional 10-10′ direction,according to an embodiment of the present invention.

DETAILED DESCRIPTION

In one embodiment of the present invention, a signal line of an LCDpanel is disposed on a TFT substrate, and a repair line of the LCD panelis disposed on a color filter substrate. FIG. 3 illustrates a top viewdiagram of a TFT substrate 30 of an LCD panel 50 according to thepresent invention. FIG. 4 illustrates a top view diagram of a colorfilter substrate 40 of an LCD panel 50 according to the presentinvention.

In FIG. 3, a plurality of parallel data lines D1-Dm and a plurality ofparallel scan lines S1-Sn are disposed in a display area 35 of the TFTsubstrate 30. The data lines D1-Dm and the scan lines S1-Sn areintersecting and form a pixel matrix 32. Each pixel and correspondingpixel driver IC formed by electrical components such as TFTs andcapacitors is represented as a dot in FIG. 3. A source driver IC and agate driver IC of the LCD panel 50 are packaged in a tape carrierpackage (TCP) manner and are represented as TCPs 44 and 46 of FIG. 3.The data lines D1-Dm can be coupled to a printed wiring board (PWB) 34through the TCP 44 and can receive signals transmitted from the sourcedriver IC, and the scan lines S1-Sn can be coupled to a PWB 36 throughthe TCP 46 and can receive signals transmitted from the gate driver IC.Connecting wires CU1-CUs and CL1-CLs are respectively disposed at twoends of the display area 35 and are respectively intersecting at twoends of the corresponding data line. An end of the connecting wiresCU1-CUs respectively includes pads U1′-Us′, and an end of the connectingwires CL1-CLs respectively includes pads L1′-Ls′. Under normalcircumstances, the connecting wires CU1-CUs and CL1-CLs and the datalines D1-Dm are not electrically connected.

In FIG. 4, repair lines R1-Rs of the LCD panel 50 are disposed on thecolor filter substrate 40. As the surface of the TFT substrate 30 isdisposed opposite to the surface of the color filter substrate 40, anarea 45 of the color filter substrate 40 corresponds to the display area35 of the TFT substrate 30. Two ends of the repair lines R1-Rs includepads U1-Us and L1-Ls, respectively. The pads U1-Us and L1-Ls arerespectively disposed at locations corresponding to the pads U1′-Us′ andL1′-Ls′.

A black matrix, a plurality of color filters (CFs), and a counterelectrode of a transparent electrical conductive layer are also disposedon the color filter substrate 40. FIG. 5 illustrates a cross-sectionaldiagram of a color filter substrate 40 of the LCD panel 50 along asectional 5-5′. The color filter substrate 40 shown in FIG. 5 includescolor filters 51-54, a black matrix 77, a flat layer 55, a transparentelectrical conductive layer 56, and repair lines R1-R2, and the TFTsubstrate 30 includes data lines D1-D3. A liquid crystal layer 59 isinterposed between the TFT substrate 30 and the color filter substrate40. As the surface of the TFT substrate 30 is opposite to the surface ofthe color filter substrate 40, the order sequence of each layer of colorfilter substrate 40 as illustrated in FIG. 5 is opposite to the formingsequence of each layer of color filter substrate 40, as this ispresented in a different manner, the black matrix 77 in the figure canbe located either on the top or the bottom of the color filtersubstrate. While only the top side is used for explanation herein, thisis not a limitation of the present invention.

In the embodiment of FIG. 5, the color filters 51-54 can be red, green,or blue color filters disposed over the top of the color filtersubstrate 40 corresponding to a position between the data lines D1, D2,and D3. The black matrix 77 is installed between each color filter forblocking interference between different color lights such as red, green,and blue, and also for preventing any light leakage when the user viewsat an angle. The flat layer 55 is formed over the color filters 51-54and the black matrix 77 to provide a flat surface for subsequentprocesses. The transparent electrical conductive layer 56 is utilized asa counter electrode of the LCD panel 50 which can be made of indium zincoxide (IZO) or indium tin oxide (ITO). The repair lines R1 and R2 eachinclude a conductive layer 57 and an insulating layer 58 disposed at aposition corresponding to the black matrix 77.

Next, in the following, a connecting method of the connecting wiresCU1-CUs and CL1-CLs with the repair lines R1-Rs is explained. FIG. 6illustrates a cross-sectional diagram of the LCD panel 50 alongdirection of the repair line R1. The pads U1 and L1 at two ends of therepair line R1 are respectively coupled to the pads U1′ and L1′ of theTFT substrate 30 through a electrically conductive material 60 (such asa silver glue) such that the repair line R1 and the connecting wires CU1and CL1 can be electrically connected.

FIG. 7 illustrates a resolution for the LCD panel 50 when an opencircuit occurs in a data line. If the open circuit occurs at point A ofthe data line D1 (the open circuit is illustrated as “x” in FIG. 7), themethod can utilize a laser welding method to respectively connect pointB and point C of the data line D1 to the conducting wires CU1 and CL1.The connecting point of the data line D1 and the conducting wires CU1and CL1 is represented as “▴” in FIG. 7. At this time, signals are beingtransmitted from an end of the data line D1 to the repair line R1through the pad U1′, the electrically conductive material 60 and the padU1, and then the signals are transmitted to the other end of the dataline D1 through the pad L1′, the electrically conductive material 60 andthe pad L1. The arrows of FIG. 6 represent the signal transmission routeat the moment of time. Since the repair lines R1-Rs of the presentinvention are disposed over the color filter substrate 40 instead ofover the TFT substrate 30 like the data lines D1-Dm, it is not requiredto dispose the repair lines R1-Rs in order to avoid the data lines D1-Dmand other components as in the conventional method. Thus, the length ofthe repair lines R1-Rs are identical to that of the data lines D1-Dm.When there is an open circuit in the data line, a low resistance valuetransmission route can be provided to effectively lower the RC delayeffect and power consumption of the LCD panel 50.

FIG. 8 illustrates a diagram of an embodiment of the present invention.FIG. 8 can also illustrate a cross-sectional diagram of the color filtersubstrate 40 of the LCD panel 50 along the sectional 8-8′ direction. InFIG. 8, color filters 81-84 can be red, green, or blue color filtersdisposed over corresponding positions between data lines D1, D2, and D3.A black matrix 99 is formed between each color filter for blockinginterference between different color lights, such as red, green, andblue, and also for preventing any light leakage when the user views atan angle. A flat layer 85 is formed over the color filters 81-84 and theblack matrix 99 to provide a flat surface for subsequent processes. Atransparent electrical conductive layer 86 is utilized as a counterelectrode of the LCD panel 50 which can be made of indium zinc oxide(IZO) or indium tin oxide (ITO). In the embodiment of FIG. 5, the repairlines R1 and R2 are further formed on the transparent electricalconductive layer 56. In the embodiment of FIG. 8, the repair lines R1and R2 are manufactured in an etching process and can be defined bydirectly corresponding to a position of the black matrix layer 99 on thetransparent electrical conductive layer 86.

In the above-mentioned embodiment, the repair lines are formed on thetransparent electrical conductive layer 56 and correspond to position ofthe black matrix layer 77, or the repair lines can be defined bydirectly corresponding to the position of the black matrix layer 99. Asthe black matrix layers 77 and 99 are utilized for blocking light,therefore installation of the repair lines of the present invention willnot affect an opening rate of the LCD panel 50. However, the presentinvention is not limited to the structure formed by disposing the repairlines corresponding to the position of the black matrix, as long as therepair lines are disposed on the color filter substrate to substitutethe open circuited data line of the TFT substrate of the LCD panel,which falls within the metes and bounds of the present invention.

In the embodiment of FIG. 5 and FIG. 8, in each set of data lines (suchas data lines D1-D3) only two repair lines are provided, however thepresent invention can also provide more sets of repair lines. In orderto avoid affecting the opening rate as mentioned, a repair line can bedisposed on the transparent electrical conductive layer 56 to correspondto a position of the black matrix layer 77, such as the repair lines R1,R1′, and R2 illustrated in FIG. 9 (cross-section 9-9′ of FIG. 4).Alternately, each repair line can be defined directly corresponding tothe position of the black matrix layer 99 on the transparent electricalconductive layer 86, such as the repair lines R1, R2, and R2′ shown inFIG. 10 (cross-section 10-10′ of FIG. 4).

According to another embodiment of the present invention, the repairlines are disposed on the TFT substrate, and the data lines are disposedover a different substrate. Therefore, it is not necessary to avoid thedata lines and other components when disposing the repairing lines as inthe conventional method. Thus, the length of the repair line, accordingto one embodiment of the present invention, is identical to the lengthof the data line. When there is an open circuit in the data line, a lowresistance transmission route can be provided to effectively lower theRC delay effect and power consumption of the LCD panel. Furthermore,with more available space on the TFT substrate, more repair lines can beprovided to increase the repair ability without lowering the openingrate. In comparison to the prior art, the present invention provides anLCD panel with a low RC effect, low power consumption, and high repairability.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

1. A display panel comprising: a first substrate; a second substrate; aplurality of signal lines formed over a first side of the firstsubstrate; a transparent electrical conductive layer formed over a firstside of the second substrate facing a first side of the first substrateand utilized as a common electrode; a plurality of repair lines formedover the first side of the second substrate at a same level as thetransparent electrical conductive layer; a first connecting wire formedover the first substrate, intersecting a first end of a correspondingsignal line among the plurality of signal lines, and coupled to a firstend of a corresponding repair line among the plurality of repair linesthrough an electrically conductive material; and a second connectingwire formed over the first substrate, intersecting a second end of thecorresponding signal line, and coupled to a second end of thecorresponding repair line through the electrically conductive material.2. The display panel of claim 1, wherein the corresponding signal linehas an open circuit, and the first and the second connecting wires arecoupled to the corresponding signal line.
 3. The display panel of claim1, wherein the first connecting wire is coupled to the first end of thecorresponding repair line through an electrically conductive material,and the second connecting wire is coupled to the second end of thecorresponding repair line through an electrically conductive material.4. The display panel of claim 1, further comprising a first padinstalled at an end of the first connecting wire, and a second padinstalled at an end of the second connecting wire, wherein the first padis coupled to the first end of the corresponding repair line through anelectrically conductive material, and the second pad is coupled to thesecond end of the corresponding repair line through an electricallyconductive material.
 5. The display panel of claim 1, further comprisinga first pad and a second pad formed at both ends of the correspondingrepair line, wherein the first connecting wire is coupled to the firstpad through an electrically conductive material, and the secondconnecting wire is coupled to the second pad through an electricallyconductive material.
 6. The display panel of claim 1, further comprisinga first pad formed at one end of the first connecting wire, a second padformed at one end of the second connecting wire, and a third pad and afourth pad respectively formed at both ends of the corresponding repairline, wherein the first pad is coupled to the third pad through anelectrically conductive material and the second pad is coupled to thefourth pad through an electrically conductive material.
 7. The displaypanel of claim 1, wherein one of the plurality of signal lines comprisesa scan line and a data line to form a pixel matrix.
 8. The display panelof claim 7, further comprising a plurality of thin-film transistorsdisposed at each intersection of a scan line and a data line forcontrolling each pixel within the pixel matrix.
 9. The display panel ofclaim 1, further comprising a plurality of color filters disposed overthe first side of the second substrate, each color filter correspondingto a position between two adjacent signal lines.
 10. The display panelof claim 9, further comprising a plurality of black matrix layers formedover the second substrate, each black matrix layer corresponding to aposition between two adjacent color filters.
 11. The display panel ofclaim 7, wherein the corresponding repair line is disposed so as tocorrespond to the corresponding data line.
 12. The display panel ofclaim 1, wherein the second substrate comprises a flat layer, and thetransparent electrical conductive layer and one of the plurality ofrepair lines are disposed on the flat layer.
 13. The display panel ofclaim 1, wherein the transparent electrical conductive layer comprisesindium zinc oxide or indium tin oxide.
 14. The display panel of claim 1,further comprising an insulating layer formed between the transparentelectrical conductive layer and the corresponding repair line.
 15. Thedisplay panel of claim 1, wherein the first substrate is a thin filmtransistor substrate, and the second substrate is a color filtersubstrate.
 16. The display panel of claim 1, further comprising a liquidcrystal layer interposed between the first substrate and the secondsubstrate.